x := 1;
y := 2;

define add proc()
   x := x + y;
   return := 0
end;

define second proc(p)
   x := 2;
   l := p();
   return := 0
end;

define first proc()
   y := 3;
   m := second(add);
   return := 0
end;

n := first();
z := x
